09Sound attenuating louvres

Sound attenuators

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Sound attenuators, Sound attenuating louvres

Sound attenuators are designed to attenuate fan and air-conditioning device noises in ventilation ducts, and to prevent propagation of noise between rooms.

Sound attenuators, Sound attenuating louvres

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Sound attenuators, Sound attenuating louvres

Sound attenuators

Sound attenuators are designed to attenuate fan and air-conditioning device noises in ventilation ducts, and to prevent propagation of noise between rooms.

Sound attenuators DZ-2 and DZ-3DZ-2 sound attenuators field of applicati-on is the attenuation of fan noise in ven-tilation and air-conditioning installations. They provide very efficient attenuation in the 250 Hz octave band. K-2 splitters built in these attenuators consist of alternant layers of absorbing material and galvanised steel sheet membranes.DZ-3 sound attenuators field of applica-tion comprises attenuation of industrial machinery noises and special applicati-ons in air-conditioning systems. They pro-vide very efficient attenuation in the 500 to 4000 Hz frequency range. K-3 splitters built in these attenuators have their entire surface made of absorbing material.

Round sound attenuators ODZ-1ODZ-1 round sound attenuators are applied in ventilation and air-conditioning systems for attenuation of fan noises. They are suitable for installation in either inlet or outlet pipes of axial fans, in inlet pipes of radial fans, or installation in circular cross-section ducts.

Round sound attenuators MDZ-50MDZ-50 round sound attenuators prevent propagation of noise between rooms through ventilation ducts.

Sound attenuating louvres

Steel attenuating louvres JAR are desi-gned to prevent ingress of outside noises into the building interior, or propagation of noises from the building into the enviro-nment, through supply or exhaust openin-gs. In addition to their acoustic protection function, they also serve as conventional protection louvres.

Overview

Round sound attenuators ODZ-1

Round sound attenuators MDZ-50

Sound attenuating louvres JAR

Rectangular sound attenuators DZ-2, DZ-3

DZ-2, DZ-3 splitters K-2, K-3

ODZ-1

MDZ-50

JAR

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Sound attenuators, Sound attenuating louvres

ContentPage

SOUND ATTENUATORS 340

Rectangular sound attenuators DZ-2, DZ-3 340

Circular sound attenuators ODZ-1 352

Circular sound attenuators MDZ-50 355

SOUND ATTENUATING LOUVRES 357

Sound attenuating louvres JAR 357

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Sound attenuators, Sound attenuating louvres

K-2

K-3

Sound attenuators Rectangular sound attenuators DZ-2 in DZ-3

ApplicationSound attenuators are designed to attenuate noises of fans and air-conditioning devices in ventilation and air-conditioning instal-lations. Noise has a strong negative impact on working efficiency and general feeling of occupants. Damages to the central nervo-us system, deafness and other ailments are threats to persons working in noisy environments.

Application of sound attenuator DZ-2DZ-2 sound attenuators are designed to attenuate fan noises in ventilation and air-conditioning systems. Based on numerous practical calculations it has been established that the said systems require maximum sound attenuation in the 250 Hz octave band. The sound attenuation performances of the DZ-2 sound attenuators with built-in K-2 attenuation splitters are far superior to those of classical absorption attenuators with equal length and width of splitters and equal splitter pattern pitch. In other frequency bands, attenuation performances of the DZ-2 attenuators are also well adapted to venti-lation and air-conditioning systems acoustic requirements.

Application of sound attenuator DZ-3DZ-3 sound attenuators are suitable to attenuate industrial machinery noises and for special applications in the air-conditi-oning engineering. DZ-3 sound attenuators provide very efficient attenuation in the 500 to 4000 Hz frequency range.

DescriptionThe attenuator housing is made of galvanised sheet steel. The ho-using connecting flanges are made of galvanised rolled steel quick--coupling elements with 30 mm edges, joined by means of angle pieces. Splitters with frames of galvanised sheet steel and filling of highly efficient absorption material are built into the housing. Filling exposed surface is protected with cellulose foil. They are designed to be incombustible. Contrary to K-3 splitters, the filling of K-2 atte-nuation splitters is partly covered with galvanised sheet steel strips. Strips of galvanised sheet steel or cellulose foil run along the splitter length L. Hence, the K-2 attenuator splitter height H and length L are not interchangeable. The splitter L dimension shall always run in the direction of propagation of sound.

DimensionsAttenuator sizes are determined by use of the Klima DZ com-puter program in accordance with the customers requirements. Splitters alone can also be delivered. All sound attenuator sizes are derived from the unit modular length R=250 mm. All sound attenu-ator model lengths and heights are multiples of the said R modular length, which allows economical and low-cost production.

Determination of adequate attenuatorSplitter thickness d=100 mm is suitable for smaller air flow rates as well as in the cases where high degree attenuation is required in the high frequency range. Splitter thickness d=200 mm is suitable for large air flow rates as well as in the cases where high degree attenuation is required in the low frequency range. The computer program automatically calculates the required distance (s) between splitters. In comparison with standard cellulose foil lining design, the noise attenuation capacity of splitters with polyethylene foil lining is

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Sound attenuators, Sound attenuating louvresSound attenuators

Attenuation

500 Hz 1000 Hz 2000 Hz 4000 Hz 8000 Hz

D 14 % 36 % 50 % 50 % 50 %

Ordering key

n Number of splittersd Splitter thicknesse (d=100 or d=200)

V Guides to reduce pressure drop on both sides

P Perforated steel sheetF Polyethylene foil

DZ-2, DZ-3 Sound attenuator type

DZ-2 / F / P / V / d / n B x H x LOrdering key

d Splitter thickness (d=100 or d=200)

V Guides to reduce pressure drop on both sides

P Perforated steel sheetF Polyethylene foil

K-2, K-3 Attenuation splitter type

K-3 / F / P / V / d H x L

dB

Hz

inferior. The differences are observed in the frequency range from 500 Hz up. Attenuation capacities are reduced as follows:

Permissible air velocities across splittersWith the standard version-outer filling surface protected with cellulose foil or sheet steel plates - air velocities of up to 20 m/s are permissible. By installing a perforated galvanised steel sheet in front of the cellulose foil, this upper limit can be increased to 30 m/s. In conditions of dusty or damp air, cellulose foil lining shall be supplemented by polyethylene protection foil and a protection scre-en. This latter design can sustain air velocities of up to 30 m/s.

Temperature range standard version: up to 100 C, when protected with polyethylene foil and screen: up to 80 C.

Attenuation capacitiesAttenuation capacities are measured in our in-house laboratory.In cases where the required attenuation rates exceed the capacities achievable with attenuators of sizes limited by installation constraints, several attenuators may be installed in series. However, because of lateral sound propagation (through the attenuator housing and splitter frame), attenuation rates exceeding 40 dB, across the entire frequency spectrum, can not be achieved by means of a single attenuator. Higher attenuation rates can only be achieved by adding another attenuator - located as far away as possible from the first one.

CautionWhen installing attenuator splitters in different ducts, ensure that the duct height does not exceed the height of splitters. Any gap between the duct w